In the haemolymph of the cockroach Diploptera punctate ASTs were suggested to be important regulatory peptides of the immune response (107) and in Litopenaeus vannamei, transcripts for the three AST peptide precursors (AST-A, AST-B/MIP and AST-C) were up-regulated in the haemocytes 6 hours after infection with the white spot syndrome virus (12). This evidence concerns the gene MIP and infection.